Chancellor Werner Faymann bowed out earlier this week, with the Social Democrats hit by a string of electoral losses to the right and a split between proponents and opponents of Mr Faymann's hard-line migrant policies.

Mr Kern still faces a potential hurdle. The centrist People's Party, the junior coalition partner, has signalled that it will only accept a replacement who backs the tough migrant restrictions - something Mr Kern has stayed silent on so far.